The present invention relates to a process for preparing flexible blocks which can be used for printing in flexography, typography or dry offset. The present invention also relates to a device for implementing the process.
More exactly, the invention relates to a process for processing photopolymer plates of any format very quickly, in order to convert them into printing blocks.
It is already known that it is possible to obtain a block for flexography or typography by exposing a plate of a photopolymer which is sensitive to ultraviolet radiation, with the interposition of a negative film which leaves exposed to the radiation those zones which are to come into relief on the finished block.
The radiation hardens these zones, and the material from the protected surface is subsequently removed by brushing it using plane or rotary brushes or by spray nozzles; a solvent or water acting as wetting agent. The operation is continued until the zones which have been exposed are sufficiently in relief.
A first object of the invention is complete automation of the whole of the etching process.
Moreover, a wide range of photopolymer plates of all thicknesses and in all formats (up to 50.times.80 inches) are currently found on the market, and semi-automatic machines are already manufactured for producing them. In operation, the photopolymer block is fixed or bonded onto the block holder tray, and a plane brush with orbital movement, immersed in an etching bath, makes it possible to prepare blocks.
Another aim of the invention is therefore to prepare photopolymer blocks of all formats and thicknesses, in a simple machine, which allows an already exposed block to be introduced on one side of the machine, and to be taken out after etching, almost dry, in a minimum amount of time.